IFC modeling of Samples (Tunnel/Geotechnics domain)

[larswik]

From your answers, I have to stick to the proposal above. You are talking about Materials in IFC.

Expecting that laboratories would produce IFC files is in my view a bit far fetched. Maybe a bit more than a bit. 😄 There are other materials of which the characteristics come from laboratories but none of them incorporate the samples that were used for testing.

In a nutshell, the requirements listed imply that you need the material characteristics which are located somewhere. That is a typical IfcProduct (something spatial or physical - in our case physical) with an assigned material. I do not see other requirements.

Originally posted by @SergejMuhic in https://github.com/bSI-InfraRoom/IFC-Specification/issues/422#issuecomment-1170260337

[mbeaufils]

Completing what @j-weil wrote, but maybe focusing more on the perspective for BIM / IFC.

First : A MaterialSample aka Sample/Specimen is something collected from the field (piece of soil, rock, fluid) that is then studied in a laboratory. Several tests will be performed on them to identify their characteristics. In a MaterialSample, several materials (here with the same meaning as IfcMaterial) can be found. They can then be studied separately.

For us, IfcMaterial would be a property of an object, a kind of geoscience observation. Whereas with the expected IfcMaterialSample we would like to have a concept that represent the physical object that has been collected on the field and on which we expect to associate several lab tests.

The MaterialSample would be positionned where it has been collected. It will be a point. We also expect to be able to describe sub sampling: MaterialSamples built from MaterialSamples.

Expected benefits of that approach:

• Highlights dependencies between observations (if they are made from the same MaterialSample),
• Reduction of the amount of info attached to the geoscience observation (provision of the Id of the MaterialSample, instead of repeating the geoscience observation location),
• Reduction of the amount of the objects at the same place: as a lot of geoscience observations are made from the same borehole or materialSamples. Having a geometry for each geoscience observation would lead to a lot of objects at the same location.

Also I am not sure that laboratories will use IFC for sharing their data, yet in terms of exchange scenario when Book A data are exchanged (in order to be inputs for Book B) the description of the MaterialSamples should be included. Geomodellers would be interested in seing the Boreholes, MaterialSamples sampling locations, ObservedZones and then discover the associated geoscience observations.

[SergejMuhic]

What remains open is how MaterialSample is embedded into the BIM use case, exchange scenario, exchange model, data responsibility and authorship, classification, project structure environment...

I am not trying to achieve anything other than get my questions answered. We, as the IFC technical team just need all of the questions answered to properly model the requirements of domain experts. We need to establish where to put MaterialSample in the inheritance tree. Whether or not this is accepted into the data model is not up to us, it is up to the SCTE.

To clarify, I was not talking about IfcMaterial but how Materials are used in IFC. There is a single material representation, a layered material representation, a material constituent representation and a material profile representation. Saying that IfcMaterial is a property of an object is misleading as it is a concept of its own and can hold material properties. It is not independent i.e. a rooted object with a GUID meaning it has to be attached to something tangible but it is not a mere property.

The notion of representing the built environment is the guiding principle in IFC. How MaterialSample fits into it can only be established after we answer the many questions from my original post (probably more will emerge in the process). Maybe the main question we need to answer is whether MaterialSample is a standalone type or a resource, followed immediately by is it a product (something supplied, created or manufactured) then by all the rest repeated above and formulated in my original post. I do not see other possibilities. Maybe the only other one would be whether it is a resource (properties of something used in a process).

[mbeaufils]

Hi @SergejMuhic, we will have a geosubgroup meeting tomorrow with @j-weil but here are some comments to make the discussion move forward.

To clarify, I was not talking about IfcMaterial but how Materials are used in IFC.

Yes the way materials are considered in geotech is quite different. We have to be cautious not to do wrong connections.

Maybe the main question we need to answer is whether MaterialSample is a standalone type or a resource, followed immediately by is it a product (something supplied, created or manufactured) then by all the rest repeated above and formulated in my original post. I do not see other possibilities. Maybe the only other one would be whether it is a resource (properties of something used in a process).

In terms of usage, a MaterialSample has similarities with Borehole as both are objects that can be mapped and are associated to geoscience observations. As IfcBorehole is defined as an IfcGeoscienceElement, I believe a MaterialSample should be an IfcGeoScienceElement too. As explained by Lars in #422 it seems that an IfcGeoScienceElement is an IfcProduct, so I would say yes a MaterialSample should be an IfcProduct (even if the semantic definition "something supplied, created or manufactured" could be discussed for all our geoscience objects).

[j-weil]

07.07.2022, comments by Geo Subgroup regarding discussion of “sample” in conceptual model

Initial proposal: „MaterialSample“ with related objects „LabTest“

Existing concept for “materials” in IFC: http://ifc43-docs.standards.buildingsmart.org/IFC/RELEASE/IFC4x3/HTML/ifcmaterialresource/content.html Description: “The schema IfcMaterialResource contains the types and entities that are used to define materials (substances, of which products are made of).”

Comment Geo: This concept of materials was not considered for “ground materials” and elements we defined (like GeologicalUnits, GeotechnicalUnits,…)

We understand the terminology is causing the main issues here, because IFC has a quite detailed concept for “materials”. Maybe an alternative name for that object could help. Our initial term “sample” is still the first choice as there is a very clear definition for the domain, e.g. in Eurocode and standards.

Answers to questions by Sergej:

• MaterialSample is a standalone type or a resource: We are not 100% clear about the definition of the two options. We would consider it to be a “standalone type”, similar to other “SpatialGeoObsElements” like “borehole” or “MappedZone”. We understand that objects defined as “resources” are dependent on other objects, while we see it the other way around: The “sample” is independent = standalone, and “LabTests” are depending on it.

- is it a product (something supplied, created or manufactured) Yes

- how MaterialSample is embedded into the BIM use case - exchange scenario - exchange model

Use cases from RA: 1b Geologic factual data: Producer of the IFC file:

• Person responsible for executing the site investigation, providing the results to the person who does the interpretation and geological/geotechnical modelling.
• Organization that hosts a database with lab test results and provides the information in IFC format Purpose:
• use the “LabTest” information (key-parameters, measured properties) as a base for modelling and spatial, geostatistical assessment (also for definitions of uncertainty)
• Use it as a digital representation / attachment to a GDR, a “Geotechnical Data Report” or “Factual Data Report”
• visualization: points of information that have been used, as a proof of the factual base of the interpretation

Receiving software:

• Common coordination model, “federated model”, which is not able to consume the more “domain specific” formats like AGS, DIGGS,… The benefit would be that the information is available from that one central platform, and no alternative “geo-coordination models” etc. are necessary.

Use cases from RA: 15b Geologic documentation: Producer of the IFC file: Contractor who loccects samples during excavation, fro documenting the encountered, “as built” ground conditions, e.g. rock strength, abrasiveness, providing the results to the person who does the comparison to the prognosis model Purpose: -comparison of encountered vs. expected/baseline conditions

Exchange model: Collections of GeoScienceElements” like (multiple) “Sample”, “Borehole”, “MappedZone”, “LabTest”, “InSituTest”, depending of the scope of the investigations that are performed

data responsibility and authorship

1. option: Person responsible for executing the site investigation, providing the results to the person who does the interpretation and geological/geotechnical modelling.
2. option: Person responsible for producing the GDR, after collecting site investigation results from different contractors who executed the works

• classification Not sure in which context, referring to our taxonomy? See first point, “standalone type” etc.

• project structure environment... Can you specify this question in more detail? Maybe answered by comments to “Use Cases”?